Chapter 3 Quiz Questions

Identify functions of ATP

1. To power the movement of cells 2. To drive energetically unfavorable reactions 3. To power transport across cell membranes

In order to obtain a stable outer shell of electrons, carbon forms four: 1. covalent bonds 2. hydrogen bonds 3. ionic bonds 4. double bonds

1. covalent bonds

What is the function of chaperone proteins? 1. They transport nucleic acids into and out of the nucleus. 2. They help other proteins fold correctly. 3. They transport proteins into and out of the cell. 4. They transport proteins from one part of the cell to another. 5. They function as receptors for chemical messengers.

2. They help other proteins fold correctly

If a DNA double helix is composed of 20% A, then the percentage of T is...

20%

Which group of biomolecules is the most efficient for storing energy? 1. Monosaccharides 2. Nucleic acids 3. Fats and oils 4. Polysaccharides 5. Proteins

3. Fats and oils

Which of the following is an accurate description of a triglyceride? 1. Three glycerol molecules joined to one fatty acid 2. A hydrocarbon chain bound to 3 carboxyl groups 3. One glycerol molecule joined to three fatty acids 3. A three-carbon chain where each carbon is bound to a hydroxyl group

3. One glycerol molecule joined to three fatty acids

Choose all that apply: Compared to an unsaturated fat, a saturated fat with the same number of carbon atoms will have which of the following? A. A higher melting point B. More hydrogen atoms C. More double bonds

A and B

Select all that apply: Compared to an unsaturated fat, a saturated fat with the same number of carbon atoms will have which of the following? A. A higher melting point B. More double bonds C. More hydrogen atoms

A and C

Choose all that apply: Which of the following are functions of proteins? A. They catalyze chemical reactions. B. They provide structural support for many animal tissues. C. They transport ions and molecules across cell membranes. D. They play a key role in the contraction of muscles. E. They are the main component of plant cell walls. F. They are the most efficient molecules for storing energy.

A, B, C, D

Choose all that apply: From the following list, choose all lipids. A. Fats B. Terpenes C. DNA and RNA D. Oils E. Polypeptides

A, B, D

Choose all that apply From the list below, select all that are polysaccharides. A. Glycogen B. Starch C. Fructose D. Cholesterol E. Chitin F. Cellulose

A, B, E, F

Choose all that apply: Protein denaturation may be caused by an increase in which of the following? A. pH B. The concentration of chaperone proteins C. Temperature D. Ionic concentration

A, C, D

Select all that apply: Which of the following are common steroids? A. Testosterone B. Phospholipids C. Estrogen D. Triglycerides E. Cholesterol

A, C, E

How can scientists use protein motifs? A. They can be used to predict the function of a protein B. They can be used to determine if a protein has any domains (and how many) C. They can be used to determine how a protein folds in different conditions (pH, temperature, etc.)

A.

How do saturated and unsaturated fats differ in their ability to pack together? A. Unsaturated fats cannot pack as tightly as saturated fats because of the presence of double bonds between the carbon atoms. B. Saturated fats cannot pack as tightly as unsaturated fats because of the lack of double bonds between the carbon atoms. C. There is no difference in the ability of saturated and unsaturated fats to pack together.

A.

How many polypeptides are present in a protein whose highest level of structure is tertiary structure? A. 1 polypeptide only B. 3 polypeptides that interact to form the protein It is impossible to determine from the information given C. 2 polypeptides that interact to form the protein

A.

The sequence of amino acids in a protein is specified by which of the following? A. The sequence of nucleotides in a segment of DNA B. The alternating sugar-phosphate groups in the DNA backbone C. Special protein-synthesizing enzymes D. The overall 3-dimensional shape of the protein

A.

What is the primary structure of a protein? A. The amino acid sequence of the polypeptides. B. All secondary folding in the polypeptides caused by interactions between the amino acid side chains. C. The relative frequency of different amino acids in the polypeptides. D. The interactions between amino acids that cause folding of the polypeptides. E. The sequences of secondary structural elements in the polypeptides.

A.

What are the building blocks of proteins? A. Amino acids B. Carboxylic acids C. Nucleotides

A. Amino acids

Which type of interaction plays a key role in determining both the secondary and tertiary structure of a protein? A. Hydrogen bonds B. van der Waals attractions C. Ionic bonds D. Hydrophobic exclusion E. Disulfide bridges

A. Hydrogen bonds

Glucose and fructose can be described as which of the following? A. Structural isomers B. Stereoisomers C. Enantiomers D. Isotopes

A. structural isomers

________ is often referred to as the "energy currency of the cell."

ATP

Select all that apply Which of the following describe monosaccharides? A. Monosaccharides are polymers that are formed by joining monomers called carbohydrates. B. Monosaccharides are monomers that can be joined together to form more complex carbohydrates. C. Monosaccharides are composed of carbon, hydrogen, and oxygen. D. Monosaccharides are the simplest carbohydrates.

B, C, D

Select all that apply Of the following list, choose the functions of proteins in living cells. A. They carry genetic information from one generation to the next. B. They play a key role in moving materials within cells. C. They catalyze chemical reactions. D. They are the immediate source of energy for most cell activities. E. They transport oxygen in the blood of vertebrates. F. They help the body recognize and destroy foreign microbes and cancer cells.

B, C, E, F

What are lipids? A. Lipids are hydrophilic molecules that usually lack nitrogen. B. Lipids are hydrophobic molecules composed primarily of hydrogen and carbon. C. Lipids are hydrophobic molecules that usually lack oxygen. D. Lipids are hydrophilic molecules composed primarily of hydrogen and carbon. E. Lipids are hydrophobic molecules composed primarily of carbon, hydrogen and nitrogen.

B.

Which of the following is an accurate description of the structure of an unsaturated fatty acid? A. A hydrocarbon chain with a carboxyl group at one end and no double bonds between the carbon atoms B. A hydrocarbon chain with a carboxyl group at one end and one or more double bonds between the carbon atoms C. A hydrocarbon chain with a carboxyl group at both ends and one or more double bonds between the carbon atoms D. 3 hydrocarbon chains joined to a glycerol molecule and one or more double bonds between the carbon atoms E. A hydrocarbon chain with a carboxyl group at both ends and no double bonds between the carbon atoms

B.

Fats containing polyunsaturated fatty acids have ______ melting points. A. high B. low C. no

B. Low

Which of the following determines the function of a protein molecule? A. The kinds of amino acids in the molecule, regardless of their precise sequences. B. Its shape. C. The number of amino acids in it. D. The first and the last amino acids in the protein molecule.

B. its shape

Choose all of the following that accurately describe oils, such as olive oil? A. Oils have high melting points and are solid at room temperature. B. Oils are fats that are high in saturated fatty acids. C. Oils have low melting points and are liquid at room temperature. D. Oils are fats that are high in unsaturated fatty acids.

C and D

Select all that apply Which of the following statements about carbon are true? A. A single carbon atom always bonds with four other atoms. B. The molecules it is found in are always straight chains. C. It can form covalent bonds. D. It forms the framework of biological molecules.

C and D

Select all that apply What are the three basic components of a nucleotide? A. Amino group B. Carboxyl group C. Pentose sugar D. Nitrogenous base E. Phosphate group

C, D, E

Which of the following bonds is essentially nonpolar? O--H C--N C--H C--O N--H

C--H

Select the disease type that could result from a deficiency in chaperone proteins. A. A disease caused by improper formation of chromosomes. B. A disease caused by inability to synthesize large proteins. C. A disease caused by improper folding of proteins. D. A disease caused by improper formation of membranes.

C.

The structure of a phospholipid can best be described as which of the following? A. A 5-carbon sugar joined to a nitrogenous base and a phosphate group B. A 5-carbon sugar joined to a nitrogenous base and 2 phosphate groups C. Glycerol joined to 2 fatty acids and a phosphate group D. Glycerol joined to 3 fatty acids and a phosphate group E. Five interlocking carbon rings joined to a phosphate group

C.

Where are the sugar-phosphate backbones and the nitrogenous bases located in the DNA double helix? A. The nitrogenous bases run along the outside of the double helix while the sugar-phosphate backbones pair in the middle. B. The sugar-phosphate backbones and the nitrogenous bases alternate along the length of the double helix in a specific pattern. C. The sugar-phosphate backbones run along the outside of the double helix while the nitrogenous bases pair in the middle.

C.

In general, which of the following is an accurate description of the chemical structure of FATTY ACIDS? A. A three carbon chain where each carbon is bound to a hydroxyl group B. Three hydrocarbon chains bound to each of the three carbons of a glycerol molecule C. A hydrocarbon chain with a terminal carboxyl group

C. A fatty acid is a hydrocarbon chain with a carboxyl group

Functional units within the larger structure of a protein are called ______. A. amino acids B. motifs C. domains D. tertiary structure

C. Domains

Which describes denatured proteins? A. They are usually active, but are less active than the normally folded protein. B. They usually have the same level of activity as the normally folded protein. C. They are usually inactive. D. They are usually more active than the normally folded protein.

C. They are usually inactive

When a carbohydrate is formed by linking two monosaccharides by a condensation reaction, we get water plus which of the following? A. A polypeptide B. A dipeptide C. A disaccharide D. A polysaccharide

C. a disaccharide

A phospholipid is structurally similar to a triglyceride except that in a phospholipid, a charged phosphate group replaces one of the... A. amino acids B. glycerols C. fatty acids

C. fatty acids

Lipids are composed mostly of which two elements?

Carbon and hydrogen

Which of the following help proteins fold into their correct 3-D shape? Immunoglobulins Gene regulators Hormones Enzymes Chaperone proteins

Chaperone proteins

Why do phospholipids spontaneously form bilayers when mixed with water? A. The nonpolar heads attract water and the polar tails repel water. B. The polar heads repel water and the nonpolar tails attract water. C. The nonpolar heads repel water and the polar tails attract water. D. The polar heads attract water and the nonpolar tails repel water.

D.

The two classes of nucleic acids are ______ and ______.

DNA; RNA

Changes in a protein's environment can cause the protein to unfold and lose its shape in a process called which of the following? A. Hydrolysis B. Polymerization C. Hydrophobic exclusion D. Dissociation E. Denaturation

E. denaturation

What best describes the relationship between temperature and enzyme activity?

Each enzyme has an optimum temperature where it functions best.

True or false: Protein structure is usually not affected by changes in the temperature, pH, or ionic concentration of the surrounding solution.

False. (Proteins have an optimal set of conditions where they work best, and their structure is highly sensitive to changes in environmental conditions such as temperature, pH, and ionic concentration)

Which characteristic of a protein determines its function? Shape Molecular formula Molecular weight Electrical charge

Shape

Match the non-fat lipids to their characteristics. Terpenes Steroids Prostaglandins A. Composed of four carbon rings; some function as hormones B. Long-chain lipids that are part of many biologically important pigments C. Act as local chemical messengers in many vertebrate tissues

Terpenes - B Steroids - A Prostaglandins - C

ATP contains the nitrogenous base __________, the pentose sugar ribose, and 3 __________ groups.

adenine; 3 phosphate groups

Proteins are made up of one or more unbranched chains of __________ ______

amino acids

The framework or backbone of biological molecules consists predominantly of which of the following atoms? Oxygen Carbon Nitrogen Hydrogen

carbon

________ atoms form the framework of biological molecules.

carbon

Diseases caused by the improper folding of proteins may be due to deficiencies in __________ proteins.

chaperone

Match each interaction that can potentially contribute to a protein's shape with the phrase that best describes it. disulfide bridge ionic bond van der Waals attraction hydrophobic exclusion A. formation of a covalent bond between 2 cysteine side chains B. formation of a bond between groups with opposite charge C. weak attraction between atoms due to oppositely polarized electron clouds D. hydrophobic portions of the protein gather in the interior of the protein

disulfide bridge - A ionic bond - B van der Waals attraction - C hydrophobic exclusion - D

Phospholipids always contain a ________ backbone to which three other groups/molecules are attached: one __________ group which is charged, and two long fatty acid chains, which are nonpolar.

glycerol; phosphate

In a phospholipid bilayer, the ________ regions of the phospholipids face water and the ______ regions face the interior of the membrane away from water.

head; tails

Two strands of DNA are bound together by _________ bonds and then wrapped around a common axis to form a double helix.

hydrogen

A molecule that only contains __________ and _________ is called a hydrocarbon.

hydrogen; carbon

Changes in a protein's shape can alter its ability to function or even cause it to become biologically _______.

inactive

The main chemical characteristic that lipids share is that they are _________ in water.

insoluable

A general (all-inclusive) term for organic molecules that have the same molecular formula, but that differ in their structure or in the spatial arrangement of their atoms, is ___________.

isomers

Fats containing polyunsaturated fatty acids have ______ melting points.

low

The simplest carbohydrates are ______

monosaccharides

Organisms use sequences of ___________ in their DNA to specify the sequences of _______ _______ in their proteins.

nucleotides; amino acids

Which group of molecules forms the core of all biological membranes? Phospholipids Polynucleotides Fats Polysaccharides Steroids

phospholipids

Long polymers made of monosaccharides that have been linked through dehydration reactions are called _________

polysaccharides

Match terms: primary secondary tertiary quaternary A. the overall 3-D shape of each polypeptide B. repetitive folding patterns such as alpha helix and beta pleated sheet C. how two or more polypeptides interact to form a protein D. the linear sequence of amino acids

primary - D secondary - B tertiary - A quaternary - C

The 4 main groups of biological macromolecules are nucleic acids, __________, __________, and ___________.

proteins; carbohydrates; lipids

A protein that is composed of multiple polypeptides is said to have a _________ level of protein structure.

quarternary

A fatty acid that has all the hydrogen atoms possible is said to be _______.

saturated

A fatty acid that has all the hydrogen atoms possible is said to be _________

saturated

Regarding polypeptides, the two basic types of ____________ structure are alpha _________ and beta-pleated sheet.

secondary; helix/helices

Hydrogen bonds between the amino and carboxyl groups of the polypeptide backbone help determine protein ________structure while hydrogen bonds between the amino acid side chains help determine protein ________ structure.

secondary;tertiary

Information is stored in DNA by varying the ______________ of the four types of nitrogenous bases in each strand.

sequence/order

Adenine pairs with _______ and guanine pairs with _________.

thymine, cytosine

When unsaturated fats are partially hydrogenated, this can produce double bonds with the ______ configuration, where the carbon chain is on opposites sides before and after the double bond.

trans configuration

A fatty acid that has double bonds between one or more pairs of successive carbon atoms is said to be ___________.

unsaturated